Half the length of a Biro pen, the splinter of human remains was handed over after the death of his son Jason, 31, in the September 11 attacks.

But Mr Sekzer wants more.

A retired New York police officer, Mr Sekzer believes it is time for the authorities to jumpstart their stalled efforts to reunite victims’ families with their relations' final effects, and hand over all the items that remain in storage - 15 years later.

Gathering dust in a basement in Lower Manhattan, the New York Police Department has a total of 3,483 items – among them fragments of jewellery, wallets and keys – waiting for reclamation.

A mobile phone that was retrieved from Ground Zero is seen in an exhibit at the Newseum on September 9, 2016 in Washington, DCCredit:
Alex Wong/Getty

Many of the objects are almost impossible to identify. A sliver of a necklace. Part of a watch. All neatly packaged in clear plastic bags, labelled with a barcode. But some are eminently recognisable - a softball with illegible autographs, a brass bull paperweight, car keys on a holder, an ornamental two-headed eagle.

Mr Sekzer lives in hope, even after 15 years, of recovering the Rolex watch his son bought when he was made vice-president of operations at Cantor Fitzgerald.

He told The Telegraph that the 15-year anniversary of the attacks should provide fresh impetus for efforts.

"The only thing that was ever returned of my son's body was a piece of bone fragment as long as your finger,” he said.

"I took in the picture of his watch and a receipt, what he had paid for it, and a description of what it looked like.

“I never heard anything back.

“To be honest, I wouldn't be surprised if they didn't find the watch - but I'd like to know."

A memorial for a fireman on a street near the site of the former World Trade Center in New YorkCredit:
EPA

Mr Sekzer suggested the remaining thousands of belongings should be photographed and the images placed online so that, if people recognised them, they could make claims.

He added: "I'm sure the police department wants give all these things back. Maybe they could speak to one of the big websites and ask them to provide some space to show what they have.

"If people see something they think belongs to their loved one you would have to prove ownership.

"I understand if somebody says 'that's my daughter's wedding ring' you can't just hand it over. They'd have to be very careful, I can see it's a very tough job.

“But if you don't know what's there, people don't know if it's their loved ones."

The New York Police Department memorial procession in New York last FridayCredit:
AFP

The 15th anniversary is being greeted with significantly less fanfare than the 10th.

On Sunday, President Barack Obama will speak at the Pentagon, where 184 people perished when an American Airlines jetliner slammed into the five-sided building in Arlington, Virginia.

At the site of the World Trade Centre, where 2,606 people lost their lives, a memorial for the families will be held.

Hillary Clinton, a senator for New York at the time, announced on Friday that she will attend. Donald Trump, her Republican competitor in the race for the White House, will also be there.

Last week, the US flag which was raised above the rubble and became an icon of the New York spirit of resilience in the immediate aftermath was finally returned to the site, after a hunt started by the History Channel.

The ground zero flag, as it's commonly called, went missing for years after it was lost during the clean-up of the area.

The American flag that was raised by firemen in 2001 above the site of the 9/11 attacks is displayed for the first timeCredit:
Getty

And on Sunday evening the “Tribute in Light” will once again shine into the Manhattan night sky, with 88 searchlights positioned to represent the Twin Towers beaming overnight until dawn.

Mr Obama has said he will veto the bill, but Bob Graham, the former Florida senator who was chairman of the Senate Intelligence Committee during and after the attacks, said he thought the President may change his mind.

“It’s very rare for a President to overturn a unanimous vote by both the House and the Senate,” he told The Telegraph.

And he said he welcomed calls for a public database of the items.

“I’m a great believer in transparency, so as a general answer I’d say yes,” Mr Graham said.

“Florida has a fairly liberal attitude towards accessing official documents. But the federal government is far more tedious – it can take years for the process.

“If they were to ship this very important and personal material to Florida, I believe it would be returned very quickly.”

Watch | Barack Obama dedicates weekly address to 9/11 anniversary

01:04

Other relations of the victims have backed calls for a database for personal effects.

Meg Glasser is hoping to find the wedding ring and 40th birthday present watch belonging to her husband Thomas, a partner in the investment banking firm Sandler O’Neill, who was killed in the attacks.

She recovered only a charred World Trade Centre identification card.

“It would mean the world to us” she said, adding that she would give the watch to their son, who started university this month.

She asked why the city is refusing to publicise the finds. “After all these years, it seems a little cruel,” she told the New York Post.

The New York Police Department opposes the idea of a public database, saying it would generate false claims.

“It has always been our goal to return as much property from the 9/11 disaster as possible,” said Deputy Chief Jack Trabitz, who was head of the NYPD property bureau for more than 12 years.

The police say that 87 per cent of all the items recovered have been returned.

Twisted beams and other remains from the attacks at the World Trade Center sit in Hangar 17 at New York's John F Kennedy International Airport in 2011Credit:
AP

In December 2004, the NYPD did invite relations to submit forms describing items they were looking for, so property staff could try to find a match. But it accepted the forms for only six months, ending June 29, 2005.

And no items have been reclaimed since three years ago, when a bracelet and a ring were handed back to widows.

Victims' families remain unsatisfied.

“It is beyond my comprehension why these items are kept out of view considering what they might mean to the victim’s survivors,” said Michael Conner, whose wife Margaret, 57, a Cantor Fitzgerald receptionist, was killed.

“It’s outrageous because the items belong to us – not them,” said Debby Jenkins, whose older brother Joseph Jenkins, 47, an office relocation manager, was killed while working for AON Corp in Tower 2.

“They should set up a system so that families can identify the property, instead of just putting it away and forgetting about it,” she told the New York Post.

Watch | How the 9/11 terrorist attacks unfolded

02:07

A Victims’ Compensation Fund, set up in the aftermath of the attack, has so far paid out 10,580 claims, totalling more than $2.02 billion (£1.52 billion), according to figures obtained by The Telegraph.

But the bill which overturns the ban on suing a foreign government means that the relations could potentially begin claims against the Saudi government for many millions more.

William Doyle, one of the most high-profile campaigners for victims' families, who has championed law suits against the Saudi government, accused the New York city authorities of “laziness”.

“Maybe someone can recognise something,” said Mr Doyle, whose son Joseph, 25, died while at work for Cantor Fitzgerald.